scholarly journals Update on the Inactivation Procedures for the Vaccine Development Prospects of a New Highly Virulent RGNNV Isolate

Vaccines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1441
Author(s):  
Alberto Falco ◽  
Melissa Bello-Perez ◽  
Rocío Díaz-Puertas ◽  
Matthew Mold ◽  
Mikolaj Adamek
Keyword(s):  
Fish Species ◽  
Vaccine Development ◽  
Dicentrarchus Labrax ◽  
Nervous Necrosis Virus ◽  
Farmed Fish ◽  
Virus Particles ◽  
Response Strategies ◽  
Viral Nervous Necrosis ◽  
Potential Vaccine ◽  
Uv C

Viral nervous necrosis (VNN) caused by the nervous necrosis virus (NNV) affects a broad range of primarily marine fish species, with mass mortality rates often seen among larvae and juveniles. Its genetic diversification may hinder the effective implementation of preventive measures such as vaccines. The present study describes different inactivation procedures for developing an inactivated vaccine against a new NNV isolate confirmed to possess deadly effects upon the European seabass (Dicentrarchus labrax), an important Mediterranean farmed fish species that is highly susceptible to this disease. First, an NNV isolate from seabass adults diagnosed with VNN was rescued and the sequences of its two genome segments (RNA1 and RNA2) were classified into the red-spotted grouper NNV (RGNNV) genotype, closely clustering to the highly pathogenic 283.2009 isolate. The testing of different inactivation procedures revealed that the virus particles of this isolate showed a marked resistance to heat (for at least 60 °C for 120 min with and without 1% BSA) but that they were fully inactivated by 3 mJ/cm2 UV-C irradiation and 24 h 0.2% formalin treatment, which stood out as promising NNV-inactivation procedures for potential vaccine candidates. Therefore, these procedures are feasible, effective, and rapid response strategies for VNN control in aquaculture.

scholarly journals Prevalence of Anisakis Larvae in Different Fish Species in Southern Albania: Five-Year Monitoring (2016–2020)

2021 ◽  
Vol 11 (23) ◽  
pp. 11528
Author(s):  
Enkeleda Ozuni ◽  
Ani Vodica ◽  
Marta Castrica ◽  
Gabriele Brecchia ◽  
Giulio Curone ◽  
...  
Keyword(s):  
Fish Species ◽  
Coastal Area ◽  
Sparus Aurata ◽  
Dicentrarchus Labrax ◽  
Health Impact ◽  
Coelomic Cavity ◽  
Farmed Fish ◽  
Risk Area ◽  
High Risk Area ◽  
Negative Results

Anisakidae are nematodes that commonly parasitize in the coelomic cavity and viscera of several fish species. They can be found in flesh, which is why they have an important economic and public health impact. The aim of the current work was to assess the presence and prevalence of Anisakis larvae in fish species caught in the coastal area of the Karaburun Peninsula in Vlora Bay (Albania). A total of 856 of wild teleosts and 219 specimens of farmed fish were collected over a 5-year period (from 2016 to 2020). The results showed that out of a total of 1075 analyzed samples, 361 (33.58%) were parasitized with L3 larvae. In particular, only Solea vulgaris returned negative results, while Sparus aurata, Dicentrarchus labrax, and Sardinella aurita showed the lowest prevalence (4.55%, 9.17%, and 10.53%, respectively) and mean abundance (0.84, 1.19, and 0.92, respectively). Conversely, Scomber japonicus and Scomber scombrus showed the highest prevalence (74.07% and 68.00%, respectively) and mean abundance (188.24 and 249.82, respectively). The data suggest that the coastal area of the Karaburun Peninsula (southern Albania) may be a high-risk area for zoonotic diseases, and the consumption of raw or undercooked fish caught in the Vlora district could result in the acquisition of human anisakiasis. For these reasons, it is necessary to improve the surveillance plan.

scholarly journals Mycobacterium pseudoshottsii in Mediterranean Fish Farms: New Trouble for European Aquaculture?

Pathogens ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 610
Author(s):  
Davide Mugetti ◽  
Katia Varello ◽  
Andrea Gustinelli ◽  
Paolo Pastorino ◽  
Vasco Menconi ◽  
...  
Keyword(s):  
Fish Species ◽  
Sparus Aurata ◽  
Dicentrarchus Labrax ◽  
Housekeeping Genes ◽  
The United States ◽  
Sciaenops Ocellatus ◽  
Fish Farms ◽  
Farmed Fish ◽  
Potential Threat ◽  
European Aquaculture

Mycobacterium pseudoshottsii, a slow-growing mycobacterium closely related to M. marinum, has been isolated only in wild fish in the United States and in Japanese fish farms to date. Here, we report cases of mortality in three farmed fish species (Dicentrarchus labrax, Sparus aurata, and Sciaenops ocellatus) caused by M. pseudoshottsii in Italy. Samples underwent necropsy, histology, and culture with pathogen identification based on PCR and sequencing of housekeeping genes (16S rRNA, hsp65, rpoB). Multifocal to coalescing granulomatous and necrotizing inflammation with acid-fast bacilli were observed in the parenchymatous organs, from which M. pseudoshottsii was isolated and identified. Phylogenetic analysis confirmed the results of gene sequencing and allowed subdivision of the isolates into three distinct groups. M. pseudoshottsii poses a potential threat for Mediterranean aquaculture. Its origin in the area under study needs to be clarified, as well as the threat to the farmed fish species.

scholarly journals Sea Bass Immunization to Downsize the Betanodavirus Protein Displayed in the Surface of Inactivated Repair-Less Bacteria

Vaccines ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 94
Author(s):  
Lama ◽  
Pereiro ◽  
Novoa ◽  
Coll
Keyword(s):  
Culture Media ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Surface Expression ◽  
Environmental Safety ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass ◽  
Viral Nervous Necrosis ◽  
Casein Hydrolysates

: This work describes immunization of European sea bass (Dicentrarchus labrax) juveniles against viral nervous necrosis virus (VNNV), a betanodavirus causing worldwide mortalities in many fish species. Protection was obtained with the so-called spinycterin vehicles consisting of irreversibly DNA-damaged DNA-repair-less Escherichia coli displaying at their surface a downsized VNNV coat antigen. In this work we have i) maximized bacterial expression levels by downsizing the coat protein of VNNV to a fragment (frgC91–220) containing most of its previously determined antigenicity, ii) developed a scalable autoinduction culture media for E.coli based in soy-bean rather than in casein hydrolysates, iii) enriched surface expression by screening different anchors from several prokaryotic sources (anchor + frgC91–220 recombinant products), iv) preserved frgC91–220 antigenicity by inactivating bacteria by irreversible DNA-damage by means of Ciprofloxacin, and v) increased safety using a repair-less E.coli strain as chassis for the spinycterins. These spinycterins protected fish against VNNV challenge with partial (Nmistic + frgC91–220) or total (YBEL + frgC91–220) levels of protection, in contrast to fish immunized with frgC91–220 spinycterins. The proposed spinycterin platform has high levels of environmental safety and cost effectiveness and required no adjuvants, thus providing potential to further develop VNNV vaccines for sustainable aquaculture.

scholarly journals Seasonal Evaluation of Freshness Profile of Commercially Important Fish Species

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1567
Author(s):  
Patrícia G. Cardoso ◽  
Odete Gonçalves ◽  
Maria F. Carvalho ◽  
Rodrigo Ozório ◽  
Paulo Vaz-Pires
Keyword(s):  
Fish Species ◽  
Storage Time ◽  
Sparus Aurata ◽  
Dicentrarchus Labrax ◽  
The Other ◽  
Farmed Fish ◽  
Index Method ◽  
Spoilage Bacteria ◽  
General Data

Freshness is considered one of the most important parameters to judge the quality of most fish products. In the current study, the seasonality effect on the freshness profile of different economic fish species was evaluated for the first time, using three different approaches (sensory: Quality Index Method (QIM) and European (EC) Scheme; physical: Torrymeter (TRM) values; and microbiological analyses: Total Viable Counts (TVC) and degradative bacteria). Over a year, individuals of farmed fish Sparus aurata and Dicentrarchus labrax, as well as the wild fish Trachurus trachurus, Scomber colias, and Sardina pilchardus, were sampled seasonally for the evaluation of their freshness profile over 10 days on ice. In general, data showed an increase in QIM values, a decline in TRM, and an increase of spoilage bacteria throughout the storage time, revealing a clear temporal degradation of the quality of the fish. Additionally, some signs of seasonality effect could only be observed for some species. For example, the seabass D. labrax showed lower numbers of degradative bacteria in winter than in the other seasons, suggesting a high potential to be marketed in a fresher condition, especially during that season. On the other hand, S. colias showed higher freshness scores (i.e., higher TRM values in spring and autumn and lower numbers of bacteria in summer) from spring to autumn. However, from the five studied species, S. colias presented the lowest freshness values, indicating a higher fragility of this species. This information is extremely relevant for consumers and retailers that want to invest in higher quality products, as they would thus be able to choose certain species in detriment of others. Additionally, obtained data showed that farmed species reached day 10 of storage time with lower values of QIM and microbial counts (cfu), as well as higher values of TRM, in relation to wild species. These results reinforce the idea that farmed fish can, under proper conditions, present high quality/freshness profile.

scholarly journals Mediterranean Aquaculture in a Changing Climate: Temperature Effects on Pathogens and Diseases of Three Farmed Fish Species

Pathogens ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1205
Author(s):  
Maria Chiara Cascarano ◽  
Orestis Stavrakidis-Zachou ◽  
Ivona Mladineo ◽  
Kim D. Thompson ◽  
Nikos Papandroulakis ◽  
...  
Keyword(s):  
Climate Change ◽  
Mediterranean Sea ◽  
Fish Species ◽  
Sparus Aurata ◽  
Dicentrarchus Labrax ◽  
Disease Outbreaks ◽  
Gilthead Seabream ◽  
Farmed Fish ◽  
Fish Welfare ◽  
The Mediterranean

Climate change is expected to have a drastic effect on aquaculture worldwide. As we move forward with the agenda to increase and diversify aquaculture production, rising temperatures will have a progressively relevant impact on fish farming, linked to a multitude of issues associated with fish welfare. Temperature affects the physiology of both fish and pathogens, and has the potential to lead to significant increases in disease outbreaks within aquaculture systems, resulting in severe financial impacts. Significant shifts in future temperature regimes are projected for the Mediterranean Sea. We therefore aim to review and discuss the existing knowledge relating to disease outbreaks in the context of climate change in Mediterranean finfish aquaculture. The objective is to describe the effects of temperature on the physiology of both fish and pathogens, and moreover to list and discuss the principal diseases of the three main fish species farmed in the Mediterranean, namely gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax), and meagre (Argyrosomus regius). We will attempt to link the pathology of each disease to a specific temperature range, while discussing potential future disease threats associated with the available climate change trends for the Mediterranean Sea.

scholarly journals Sea Bass Immunization to Downsized Betanodavirus Protein Displayed in The Surface of Dna-Damaged Repair-Less Bacteria

2019 ◽  
Author(s):  
Raquel Lama ◽  
Patricia Pereiro ◽  
Beatriz Novoa ◽  
Julio Coll
Keyword(s):  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Surface Expression ◽  
Environmental Safety ◽  
Small Fish ◽  
Nervous Necrosis Virus ◽  
Necrosis Virus ◽  
European Sea Bass ◽  
C Protein ◽  
Viral Nervous Necrosis

This work describes practical immunization of European sea bass (Dicentrarchus labrax) juveniles against viral nervous necrosis virus (VNNV), a betanodavirus causing worldwide mortalities in many fish species. Protection was obtained with the so called spinycterin vehicles consisting in irreversibly DNA-damaged DNA-repair-less E.coli displaying at their surface a downsized antigen. In this work we, i) maximized bacterial expression levels by downsizing the C protein to a fragment (frgC91-220) containing most of its antigenicity, ii) developed an scalable autoinduction bacterial media based in soy-bean increasing membrane display and reproducibility, iii) enriched surface expression by screening different anchors from several prokaryotic origins (anchor+frgC91-220), iv) preserved frgC91-220 antigenicity by inactivating bacteria by irreversible DNA-damage by means of Ciprofloxacin, and v) increased safety using a repair-less E.coli strain as spinycterin chassis. These second generation of spinycterins protected fish against VNNV challenge with partial (Nmistic+frgC91-220) or 100 % (YBEL+frgC91-220 ) protection, in contrast to those fish immunized with frgC91-220 spinycterins. The proposed spinycterin platform has high levels of environmental safety and cost effectiveness, thus providing potential for small fish vaccines for sustainable aquaculture.

scholarly journals Detection and Phylogenetic Analysis of Fish Viruses Inhabiting Freshwater Ornamental and Food Fish Species in India: A Survey-Based Study

2020 ◽  
Vol 5 (1) ◽  
pp. 09-18
Author(s):  
Vertika Bajpai ◽  
Divya Pragyan ◽  
Jyotirmaya Mohanty ◽  
Pramoda Kumar Sahoo
Keyword(s):  
Phylogenetic Analysis ◽  
Fish Species ◽  
Nervous Necrosis Virus ◽  
Viral Pathogens ◽  
Indian States ◽  
Fast Detection ◽  
Viral Nervous Necrosis ◽  
Cultured Fish ◽  
Fish Viruses ◽  
Comparative Phylogenetic Analysis

Molecular screening of viruses through PCR is a fast detection method and several variants of it have been developed to meet the shortcomings of conventional method. Extensive surveillance is an essential tool to have an estimate of circulating potential viruses in Indian aquatic systems. The present study focuses on standardization of semi-quantitative PCR-based diagnostics for eight freshwater fish viral pathogens and documents number of positive incidences after screening 437 numbers of samples during 2017-2020 for suspected fifteen freshwater finfish viral pathogens. Positive samples of Cyprinid herpes virus-2, carp edema virus and viral nervous necrosis virus from different regions of eastern Indian states viz., Odisha, West Bengal and Assam have given a scope of comparative phylogenetic analysis of strain variability in detail. Nevertheless, the study highlights the importance of rendering protection to native cultured fish by preventing their introduction and further spread on a local or national scale to either known or unknown susceptible fish species available in the region, and emphasize upon strengthening surveillance system.

scholarly journals Prevalence of Betanodavirus in Sea Bass (Dicentrarchus Labrax) for All Production Stages in Turkey

2021 ◽  
Author(s):  
Murat KAPLAN ◽  
Mehmet Taner KARAOĞLU
Keyword(s):  
Sea Water ◽  
Age Groups ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Epidemiological Studies ◽  
Nervous Necrosis Virus ◽  
Virus Genotype ◽  
Viral Nervous Necrosis ◽  
Water Origin ◽  
Production Stages

Abstract Viral Nervous Necrosis (VNN) is one of the most important problems in sea bass aquaculture. Although there are many studies in the world on detection and molecular characterization of betanodaviruses causative agent of VNN, there are not enough studies related to prevalance to provide epidemiological maps. The purpose of this study was to investigate the betanodavirus prevalence in all bass hatcheries actively operating and in some farms in Turkey by RT-qPCR. A total of 2460 samples including fertilized egg, prelarva, postlarva, and fingerling were collected from 16 hatcheries as covering all production stages. A total of 600 sea bass were also collected from 20 farms. Betanodavirus was detected in a hatchery and a farm in fingerling sized sea bass and prevalances were found to be 6.25% and 5%, respectively. Virus isolation initially could not be achieved in E-11 but later SSN-1. Partial genome analysis of both RNA1 and RNA2 segments of the viruses, revealed that they were Redspotted grouper nervous necrosis virus genotype endemic in the Mediterranean basin. The absence of mortality related to VNN in the hatchery and farm, the healthy appearance of the sea bass, the low viral load detected and also output of retrospective epidemiological studies indicate that the infection is subclinical. Not detecting betanodavirus in other age groups where biosafety is implemented indicates that there is no active infection. In the light of these findings, it can be concluded that there are no circulating betanodavirus in hatcheries and the detected virus could be of sea-water origin.

scholarly journals Long-Term Protection and Serologic Response of European Sea Bass Vaccinated with a Betanodavirus Virus-Like Particle Produced in Pichia pastoris

Vaccines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 447
Author(s):  
Sofie Barsøe ◽  
Anna Toffan ◽  
Francesco Pascoli ◽  
Ansgar Stratmann ◽  
Tobia Pretto ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
High Titer ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Nervous Necrosis Virus ◽  
European Sea Bass ◽  
Post Vaccination ◽  
Serologic Response ◽  
Viral Nervous Necrosis ◽  
Virus Like Particle

Viral Nervous Necrosis (VNN) causes high mortality and reduced growth in farmed European sea bass (Dicentrarchus labrax) in the Mediterranean. In the current studies, we tested a novel Pichia-produced virus-like particle (VLP) vaccine against VNN in European sea bass, caused by the betanodavirus “Red-Spotted Grouper Nervous Necrosis Virus” (RGNNV). European sea bass were immunized with a VLP-based vaccine formulated with different concentrations of antigen and with or without adjuvant. Antibody response was evaluated by ELISA and serum neutralization. The efficacy of these VLP-vaccine formulations was evaluated by an intramuscular challenge with RGNNV at different time points (1, 2 and 10 months post-vaccination) and both dead and surviving fish were sampled to evaluate the level of viable virus in the brain. The VLP-based vaccines induced an effective protective immunity against experimental infection at 2 months post-vaccination, and even to some degree at 10 months post-vaccination. Furthermore, the vaccine formulations triggered a dose-dependent response in neutralizing antibodies. Serologic response and clinical efficacy, measured as relative percent survival (RPS), seem to be correlated with the administered dose, although for the individual fish, a high titer of neutralizing antibodies prior to challenge was not always enough to protect against disease. The efficacy of the VLP vaccine could not be improved by formulation with a water-in-oil (W/O) adjuvant. The developed RGNNV-VLPs show a promising effect as a vaccine candidate, even without adjuvant, to protect sea bass against disease caused by RGNNV. However, detection of virus in vaccinated survivors means that it cannot be ruled out that survivors can transmit the virus.

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